Gas turbine propulsion systems are used to power aircraft, watercraft, power generators, and the like. A typical gas turbine propulsion system includes a gas turbine engine subsystem, an electrical power generation subsystem, a thermal management subsystem, and a lubrication subsystem.
Gas turbine engine subsystems generally include a compressor, a combustor, and a turbine. The compressor compresses air drawn into the engine and delivers high pressure air to the combustor. In the combustor, fuel is mixed with the high pressure air and is ignited. Products of the combustion reaction in the combustor are directed into the turbine where work is extracted to drive the compressor and, sometimes, an output shaft. The output shaft may drive other subsystems of the propulsion system, including the electrical power generation subsystem. Left-over products of the combustion are exhausted out of the turbine and may provide thrust in some applications. Gas turbine engines may use multiple types of engine fluids, such as lubricating oil, hydraulic fluid, fuel, and/or other engine fluids.
Typical gas turbine engines may include a magnetic chip detector to detect metallic particles in the lubricating oil. The presence of metallic particles may indicate excessive wear in one or more mechanical components of the engine. More sophisticated oil quality analysis is typically performed off-wing, in a laboratory.